On Wed, Aug 02, 2017 at 12:38:13PM -0600, Jeff Law wrote:
> On 07/17/2017 01:23 AM, Yuri Gribov wrote:
> > I've rebased the previous patch to trunk per Andrew's suggestion.
> > Original patch description/motivation/questions are in
> > https://gcc.gnu.org/ml/gcc-patches/2017-06/msg01869.html
> Is his stuff used for exception handling? If so, doesn't that make the
> performance a significant concern (ie that msync call?)
For the performance issue, I wonder if it wouldn't be better to just
compile the unwinder twice, basically include everything needed for the
verification backtrace in a single *.c file with special defines, and
not export anything from that *.o file except the single entrypoint.
That would also handle the ABI problems.
For the concurrent calls of other threads unmapping stacks of running
threads (that is where most of the verification goes against), I'm afraid
that is simply non-solveable, even if you don't cache anything, it will
still be racy.
Jakub
